Missile strikes on Syria at the weekend were an "act of aggression" which risk causing the outbreak of a wider conflict, a Russian diplomat has said.

Britain joined the US and France in mounting strikes on Syria's chemical warfare facilities after 75 people were thought to have died in a suspected chemical attack on the rebel-held town of Douma.

The ambassador of the Russian Federation to Ireland warned that Russia - the Syrian regime's principle backer - is losing "the last bit of trust" it had with the west, describing this as a "very dangerous development".

Speaking at a press conference in Dublin, Yury Filatov said the suggestion that Russia or Syria tampered with evidence to cover up the Douma attack was "absolutely ridiculous".

Russian ambassador to Ireland Yury Filatov (Niall Carson/PA)

Mr Filatov told reporters: "We have to state that the situation around Syria has deteriorated significantly.

"Obviously that is the result of the reckless actions by Washington, London and Paris.

"What is going right now is they are making every effort possible to look for the face-saving exit of the situation they themselves created.

"They are trying to whitewash their action. There is pretty much smoke around the whole thing.

"We have to call things for what they really are. The fact remains that on April 14 the United States supported by the UK and France launched an air strike against military and civilian targets in Syria.

"That was an act of aggression against a sovereign state. It was done without mandate from the United Nations Security Council and in clear violation of the UN charter or any other conceivable international law.

"We certainly condemn that in most resolute terms."

Mr Filatov spoke at the Embassy of the Russian Federation in Dublin (Niall Carson/PA)

Mr Filatov added: "The attack we have witnessed (air strikes) certainly brought the whole situation to the brink of a wider conflict which is in nobody's interests."

Russian foreign minister Sergey Lavrov has flatly denied that Russia had "tampered" with the evidence and insisted there was no proof that chemical weapons had even been used in Douma.

Mr Filatov suggested the strikes were intended to impede the investigation so nobody would know the truth, adding that experts have not yet found any traces of chlorine or any other toxic agents.

"As far as we can see there was no attack," he said, adding: "Not a single local resident was able to confirm that a chemical attack had actually taken place."

Mr Filatov said the suspected chemical attack had "definitely been staged", and said images had been "fabricated".

He denied that Russia was behind cyber attacks, saying that people try to depict Russia as being the "source of all evil" - something he described as a "really ridiculous concept".

His comments came as the UK and US issued an unprecedented joint alert on the threat of "malicious cyber activity" by the Russian state.

Meanwhile, Prime Minister Theresa May has accused Moscow of preventing inspectors for the Organisation for the Prohibition of Chemical Weapons (OPCW) reaching Douma.

Russian officials at OPCW headquarters in The Hague later said arrangements were being made for the inspectors to travel to the site on Wednesday.